s on the ground of the logical
consequences which are supposed to flow from them, nor to deny that they
could be so amended, as either to avoid the sceptical conclusions to which
our objections are taken, or be rendered innocuous by the co-existence of
other causes. Science only shows the general tendency or law of logical
connection between intellectual causes and effects. The production of the
results in particular cases is subject to exception from the introduction
of interfering causes.(1012)

Another peculiarity which appertains to the analysis of the intellectual
sources of doubt, besides the seeming absence of invariable necessity in
their operation, might be thought to destroy the practical value of the
inquiry; viz. the feeling of disappointment excited when it is perceived
that they do not wholly explain the phenomenon, and are merely antecedents
or elements, not causes. This arises from the very nature of mental
analysis. Being in nature like chemical, it aims only at the detection of
the elements that make up the compound, and furnishes the material or
formal causes, not the efficient. This longing of the mind to find causes,
and to discover the original motive power, is however a witness to the
ineffaceable connection of the idea of power with that of will. And while
it does not destroy the completeness of the analysis, as the solution of
the intellectual problem proposed, it nevertheless points to the
instinctive wish of the heart to resolve the causes of doubt into some
ultimate source in the will; and is thus a witness to the truth of the
position which we have always asserted,(1013) that the intellectual causes
selected for our special study are only one branch, and must be united to
the emotional in order to attain a full explanation of the phenomenon of
doubt.

Thus the analysis offered will have, it is hoped, a utility in the limited
sphere which was claimed for it, in supplying the account of the tangled
and subtle processes through which doubt has insinuated itself.

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What then are the lessons which the whole history teaches? To discover
these was part of our original purpose,(1014) as well as to learn the
facts and find the causes; to satisfy the longings of the heart, no less
than the curiosity of the understanding.

First, What has been the office of doubt in history? Has it been wholly an
injury, a chronic disease? or simply a gain? or